Tail regeneration in a cephalochordate, the Bahamas lancelet, Asymmetron lucayanum
Tail regeneration in a cephalochordate, the Bahamas lancelet, Asymmetron lucayanum
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DOI：
10.1002/jmor.21297
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发表时间：
2020-11-12
影响因子：
1.5
通讯作者：
Somorjai, Ildiko M. L.
中科院分区：
文献类型：
--
作者：
Holland, Nicholas D.;Somorjai, Ildiko M. L.
梭子鱼（脊索动物门，头脊索动物亚门）很容易再生失去的尾巴。在这里，我们使用光学显微镜和连续块面扫描电子显微镜（SBSEM）来描述巴哈马梭鲈（Asymmetron lucayanum）的尾部更换。截肢后一天，单层表皮在创面上迁移。第4天，再生体的长度约为去尾长度的3%。重新生长的神经索是室管膜细胞的管状外生物，脊索的新部分由几个退化的板层细胞组成，前面是许多小的空泡细胞。间皮的切割边缘突出进入再生细胞作为管状延伸。这些管彼此吻合，并在背鳍和腹鳍的再生边缘下与中线中胚层管吻合。SBSEM未发现再生细胞中任何地方有胚母样未分化细胞聚集。第6天，再生体（截尾长度的10%）包括脊索，其中上述小液泡细胞正在分化为板层细胞。在10天，再生的是截尾长度的22%：肌粒壁出现了肌细胞，并且形成了硬核。到14天，再生的尾巴长度是被切除尾巴的35%，新的组织类似于最初失去的那些小的组织。本研究结果为今后头脊索动物再生的细胞示踪、分子遗传学和基因组学研究提供了形态学背景。
Lancelets (Phylum Chordata, subphylum Cephalochordata) readily regenerate a lost tail. Here, we use light microscopy and serial blockface scanning electron microscopy (SBSEM) to describe tail replacement in the Bahamas lancelet, Asymmetron lucayanum. One day after amputation, the monolayered epidermis has migrated over the wound surface. At 4 days, the regenerate is about 3% as long as the tail length removed. The re-growing nerve cord is a tubular outgrowth of ependymal cells, and the new part of the notochord consists of several degenerating lamellar cells anterior to numerous small vacuolated cells. The cut edges of the mesothelium project into the regenerate as tubular extensions. These tubes anastomose with each other and with midline mesodermal canals beneath the regenerating edges of the dorsal and ventral fins. SBSEM did not reveal a blastema-like aggregation of undifferentiated cells anywhere in the regenerate. At 6 days, the regenerate (10% of the amputated tail length) includes a notochord in which the small vacuolated cells mentioned above are differentiating into lamellar cells. At 10 days, the regenerate is 22% of the amputated tail length: myocytes have appeared in the walls of the myomeres, and sclerocoels have formed. By 14 days, the regenerate is 35% the length of the amputated tail, and the new tissues resemble smaller versions of those originally lost. The present results for A. lucayanum, a species regenerating quickly and with little inter-specimen variability, provide the morphological background for future cell-tracer, molecular genetic, and genomic studies of cephalochordate regeneration.